Computation and communication networks typically include nodes, such as routers, firewalls, switches or gateways, which transfer or switch data, such as packets, from one or more sources to one or more destinations. The nodes may operate on the packets as the packets traverse the network, such as by forwarding or filtering the packet-based network traffic.
Nodes, such as firewalls, gateways, etc., may permit or deny transmission of packets through a network. The nodes may determine whether to permit or deny the transmission of the packets based on policies and/or rules that identify conditions that are to be satisfied before the packets can be transmitted. Some nodes may include components, such as ternary content addressable memories (TCAMs) and/or other components, that cannot process and/or execute rules that are based on negative conditions. A negative condition may, for example, identify an action that is to be performed, by a node, when a condition is deemed not to be present (e.g., when a source address, obtained from a packet, is identified as not being a particular address). Nodes that cannot execute and/or process negative conditions may reduce a degree of flexibility by which nodes can process packets.